1. Field of the Invention
The present invention relates to the dehumidification of a chamber communicating with an variable-pressure outside environment in order to keep it below a certain dew point threshold to prevent the appearance of crystals or condensation under normal conditions of use. It is indeed important in certain chambers communicating with variable-pressure outside environments, especially chambers enclosing optical projection systems, to prevent the appearance of crystals or condensation vapor that might disturb the propagation of light rays.
2. Description of the Prior Art
To do so, there are known ways of mounting a drier on the orifice through which a chamber communicates with the outside environment. This drier consists of an antechamber open on to the outside environment and filled with desiccant granulates. Thus, the air that the chamber takes from the outer environment as a result of pressure variations gets dried before it reaches the interior of this chamber.
In practice, various drawbacks are encountered. These drawbacks include especially the fact that the drier must be mounted first of all on the orifice of the to chamber and replaced from time to time in order to regenerate its granulates and the fact that, on these occasions, the chamber is in direct communication through its aperture with the outside environment. This makes it necessary each time to vent the chamber by rinsing it out with a dry gas.
It furthermore proves to be the case that the desiccant granulates are poorly utilized when they are simply heaped into an antechamber placed before the aperture of a dryer chamber, for the circulation of air follows preferred paths leading to an inhomogeneous saturation in moisture of the granulates. This makes it necessary to regenerate the granulates well before they are all saturated with moisture.
The present invention is aimed at overcoming the above-mentioned drawbacks in order to obtain a chamber with drier that is easy to maintain and subject to few constraints.